Refresher course for teachers in technical teaching aids

Fas est ab hoste doceri.

Schoolmasters will I keep within my house,
Fit to instruct her youth. * * *
* * * To cunning men
I will be very kind, and liberal
To mine own children in good bringing up.

The function of the teacher, as we have just defined it, is naturally directed toward a twofold object, interior and exterior, depending upon whether it is applied to the truth the teacher meditates upon and contemplates within himself or to the listeners whom he is teaching.